Friday, May 11, 2012

Scab and rust infection periods May 5 & 8

Wetting periods favorable for scab and cedar-apple rust infection occurred May 5-6 (13 hours wet at 63°,< 0.01 in. rain) and May 8-9 (split wetting, 18 hours at 64°, 0.4 in. rain). There are still plenty of active rust galls giving off inoculum for foliar infection. Fruit are no longer susceptible to rust infection.

Through May 10 there have been 30 days favorable for powdery mildew infection since spores were first available Mar 19.

There was scattered hail in some areas of Frederick County May 2 and fire blight shoot symptoms related to trauma blight infection are predicted to appear May 15.

The above wetting periods were also favorable for scab infection on peaches and nectarines.